A Manual Technique for Corneal Allogeneic Intrastromal Ring Segments Without a Femtosecond Laser.

PURPOSE: To evaluate the outcomes of corneal allogeneic intrastromal ring segments (CAIRS) using a simplified manual technique for treating keratoconus.

METHODS

This prospective case series included 5 eyes from 5 patients with keratoconus (4 males, 1 female, mean age 32.5 ± 10.6 years) treated with manual CAIRS. Surgeries were performed under local anesthesia by a single surgeon. An intrastromal pocket for donor tissue implantation was manually created using a spatula, and donor corneas were prepared using a Jacobs CAIRS trephine. Corneal parameters, including higher-order aberrations, coma, and spherical aberrations at a 6 mm diameter, were measured using optical coherence tomography (CASIA SS-1000, Tomey, Japan). Anterior and posterior corneal indices, subjective refractive power, cylinder, spherical equivalent, best-corrected visual acuity (BCVA; logarithm of the minimum angle of resolution [logMAR]), and central corneal thickness. Intra- and postoperative complications were also analyzed.

RESULTS

Over a mean follow-up of 6.4 ± 2.9 months, no complications occurred. BCVA improved from 0.74 ± 0.44 logMAR preoperatively to 0.19 ± 0.66 logMAR ( P = 0.043). The maximum keratometry (Kmax) value decreased from 63.6 ± 8.3D preoperatively to 59.6 ± 6.8D postoperatively ( P = 0.043). Spherical equivalent improved from -11.2 ± 5.8D to -5.3 ± 3.1D ( P = 0.043), and astigmatism reduced from -5.0 ± 3.4D to -3.3 ± 2.9D. Total corneal higher-order aberrations decreased from 5.6 ± 1.6D to 4.2 ± 1.6D postoperatively ( P = 0.043).

CONCLUSIONS

Manual CAIRS is an effective treatment when a femtosecond laser is not available.